Engine/Transmission (1998.5 - 2002) ISSPRO Mech Fuel Pressure Guage

[JTitone]

Over the weekend I changed the fuel filter in my 1998. 5. I have an ISSPRO Mechanical Fuel Pressure Guage plumbed directly from the outlet port on top of the filter housing to the guage with a shutoff valve in between. When changing the fuel filter I shut the valve running to the guage. For this latest change I went through the same routine and opened the valve slightly after restart of the engine. The filter change is always routine however the restart process is always problematic. This time after re-start, when I opened the valve to the ISSPRO, it pinned to 30psi and it's stuck at that position and won't return to 0 even after the engine is shutdown. I've tried running the engine with the valve shut and with it fully open but the needle won't move from the 30psi position. Any suggestions on getting the guage to return to normal.



Jim T.

1998. 5, SLT, 2WD, extended cab, 8 ft Linux bed, Fass DDRP, ISSPRO Mech Fuel Pressure Guage, Timbo TPS

 

[JR]

What kind of a valve do you have? Needle valves work really well. I dont ever open it up all the way, either. I set it by shutting it all the way, and with the truck running just barely crack it open a little at a time until the needle starts to slowly climb, and leave it there. This way the needle valve acts like a buffer for your gauge and doesnt "hammer it" all the time. If you dont have an isolater of some type the pulses will wear your gauge out over time. A needle valve will prevent this too.

 

[JTitone]

Hello Diesel4life. Thank you for your reply. I have a 1/4" ball valve shut off. Like you, I open the valve maybe 1/8th of the way. I never open it up all the way. This set up has worked fine over the last several years. Not sure what happened with this time as I used the same the fuel filter change process as I have on prior changes. I received an e-mail from another TDR member with a suggestion to tap the gauge to see if it will revert back to 0, but that didn't work. I'll probably end up disconnecting the plumbing and see if I can open the gauge to determine if something broke inside. If so, I'll probably try an electric gauge next time. My concern is that I'm taking a 1,000 mile trip this weekend towing a trailer and I'm sure uncomfortable making this trip without a working fuel gauge.

Thanks again

 

[Bunyan]

Call Genos and ask them for a solution. They might have your answer.

 

[JTitone]

Bunyan, thanks for the reply. When I first installed the ISSPRO several years ago, I had some tech issues with the gauge and I called Geno's. Back then they advised that I should not have bypassed the isolator that came with the kit and that by running the plumbing directly to the meter from the filter housing it could cause pre-mature failure to the gauge. Maybe the guys at Geno's were right. I'd be afraid to call them now as I might get an "I told you so. " I'm a complete dunce when it comes to electrical stuff and electronics, that's why I went with the mechanical ISSPRO. Maybe if I did have the electrical gauge I wouldn't be on this thread now.

 

[hsmith]

I have been running the Isspro mechanical gauge for several years. No isolator, just a snubber really choked down. Original one had a seepage issue which Isspro took care of promptly. With yours stuck on 30 psi, I think you will need to replace it.

 

[JTitone]

Hsmith, I'm afraid you may be right about having to replace the gauge. This time I might go with the Electric Fuel Pressure Gauge.

 

[hsmith]

If I were to redo mine I would consider the Performax by Isspro. Pricey but appealing.

 

[Bunyan]

Here's a thought. I may be wrong, but maybe there is air trapped in the line. I'd disconnect the fuel line to the guage, turn off the needle valve start the truck and slowly open the valve while the fuel line is in a container to see if air could be the culprit. When I installed my isspro mechanical fuel guage this is what I did to purge the line free of air. Maybe this will help. Also, maybe pulling a light vacumm on the guage would free the needle. Hope this helps. Let us know how it turns out.

 

[JTitone]

Hi Bunyan. Well I tried what you suggested with no luck. I took the gauge apart as far as I could and it appears like there's a spring which has sprung. With a small screwdriver I could move the needle back to 0 but when I let up it pops right back to 30. Looks like it's time for a new gauge. I'm somewhat scared without a gauge as tomorrow I'm going to be towing a trailer to South Carolina from New Hampshire.

Thanks to everyone for sharing their thoughts about my gauge issue.

 

[Bunyan]

Sorry to hear that. How old is the gauge? Maybe it's warrantied. Contact the dealer you purchased the gauge from and they may give you a new one. I've used isspro gauges for years and never had any problems. Sounds like the gauge is defective, and then somtimes things happen. I would think if you haven't had any fuel pressure problems you should be ok. If you were close I have a spare I would let you have. If your in need when you get home pm me and I can send it to you if you like. It is black face white letters green light 0-30 psi. Well be safe on your trip. Bunyan

 

[hcole]

JT, I've had this happen to me with oil pressure gauge on a machine tool. What happened was I pulled a momentary vacuum on it and it wound backward and the needle slipped on the shaft holding it. If your gauge is like mine it has a pin on the minimum and maximum to rest on. I just held the expansion tube and twisted the needle back to 0 and it worked like normal.